Credit: John Bull/COSMOS
There is another option for reuse of treated wastewater, one that is comparatively inexpensive, one that is simple, and one that would save the most water. And that option is drinking it.
The cost of building new pipes and pumps to dual-reticulate new or old suburbs, or for industrial use, is very high. And in places like Sydney, getting permission to lay new pipes - disturbing major roads and communities - can be costly and troublesome. For many places, the cost of laying those pipes could be better spent in treating the wastewater to a higher standard and connecting it back into the drinking water supply. Although most people would be surprised, this can be done safely, even producing water that is purer than the water most Australians drink today.
There are two ways in which treated wastewater is used for drinking. The first is 'indirect potable reuse', in which treated sewage is mingled with other water from which a town's supply is taken. All the towns on the Murray, including Adelaide, are indirectly drinking the wastewater of people upstream. And there are countless other Australian towns doing the same. The water supply for Sydney is downstream of the sewage outlet for Goulburn, a town of 27,000 people (and more than enough water worries of its own).
The second is 'direct potable reuse', in which the wastewater is piped directly from the treatment plant to the town's drinking water main -dubbed by opponents 'toilet to tap'. Perhaps the oldest example of the practice is in Namibia, where they have been drinking their treated wastewater since 1968.
The most powerful argument for Australians drinking their treated wastewater - directly or indirectly - is that they already are. Whether they know it or not.
But there is still a potent fear of sewage that drives opposition to recycling schemes at every level, from grassroots to government. Communities fear sewage reuse and governments fear voter backlash for proposing it. It may not be logical, but it carries punch.
Blair Nancarrow knows a bit about this fear. The director of the Australian Research Centre for Water in Society - housed in the CSIRO's Land and Water division's offices in Perth - has been researching the public's attitude to recycled water for some time. She puts the pervasive fear down to "the yuck factor".
"It hangs so much on irrational and emotive feelings," she said. "Information and knowledge doesn't seem to affect behaviour at all."
Knowledge of health risks, the treatment process and the science made no difference to whether people would try a glass of recycled water or not. "The closer it comes to personal contact, the more people get turned off by it," Nancarrow added. Watering the garden is fine, flushing the toilet is OK, doing the laundry gets a bit iffy, having a shower is more of a problem. But drinking it? Forget it.
In some respects, this attitude has the hallmarks of a phobia. The Diagnostic and Statistical Manual of Mental Disorders IV is a guide to the diagnosis of psychological problems: it defines a phobia as a "marked and persistent fear that is excessive or unreasonable". It further notes that, "the person recognises that the fear is excessive or unreasonable".
If you look at the facts of recycled water objectively, certainly fear does seem excessive and unreasonable. According to the Australian Bureau of Statistics, 1.11 million people in every 10 million are likely to have asthma in a year; 68,493 in 10 million will have their car stolen; 7.1 people in 10 million will be struck by lightning; and just one person will catch a virus from using recycled water.
